Without limiting the scope of the present invention, its background will be described with reference to producing fluid from a hydrocarbon bearing subterranean formation, as an example.
Since the beginning of oil production from subsurface formations, the industry has been concerned with efficient control of the movement of unconsolidated formation particles, such as sand, into the wellbore. For example, such formation movement commonly occurs during production from completions in loose sandstone or following hydraulic fracture of a formation. Production of these materials causes numerous problems in the operation of oil, gas or water wells. These problems include plugged formations, tubing and subsurface flow lines, as well as erosion of casing, downhole equipment and surface equipment. These problems lead to high maintenance costs and unacceptable well downtime. Accordingly, numerous methods have been utilized to control the movement of these unconsolidated formation particles during the production of fluids.
In one such method, sand control screen assemblies are interconnected within the completion string. The sand control screen assemblies are designed to allow fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough. There are numerous types of filter media that are used for such sand control screen assemblies including wire wrapped screens, prepacked screens, wire mesh screens and the like. It has been found that certain screen designs benefit from having a drainage layer between the filter medium and the base pipe of the sand control screen assembly. In one such design, the drainage layer may be formed using conventional wire wrap techniques wherein a wrap wire is wrapped around and welded to a plurality of longitudinally extending ribs such that the wrap wire forms a plurality of turns around the ribs having gaps therebetween. A multilayer wire mesh filter medium, preferably including a protective outer shroud, may be disposed around the wire wrapped drainage layer to form a sand control screen jacket which may be installed on the base pipe. Once installed on the base pipe, the ribs provide certain strength to the wire wrap and stand-off between the wire wrap and the base pipe for fluid cross flow.
It has been found, however, that such sand control screen assemblies have suffered from collapse failures in the wire mesh filter medium when the wrap wire of the drainage layer begins to spread apart and cannot adequately support the wire mesh at increased pressures. A primary cause of wrap wire spreading is wrinkling or buckling forming along the length of the wire wrap support structure which occurs as the wrap wire begins to conform to the outer diameter of the base pipe. Once wrap wire spreading occurs in the drainage layer, support is lost for the wire mesh filter medium which has led to tearing or other collapse damage to the wire mesh filter medium allowing particle infiltration therethrough.
Accordingly, a need has arisen for a sand control screen assembly that is capable of filtering fines out of a production stream from a subterranean hydrocarbon bearing formation. A need has also arisen for such a sand control screen assembly that is simple and cost-effective to manufacture and that is capable of withstanding severe downhole conditions during installation and operation. Further, a need has arisen for such a sand control screen assembly that does not suffer from collapse failures at increased pressures.